Question

Which of the following functions is a direct variation?

Answer 1

Answer:

$f(x)=2x$

Step-by-step explanation:

we know that

A relationship between two variables, x, and y, represent a direct variation if it can be expressed in the form $y/x=k$ or $y=kx$

In a direct variation the constant of proportionality k is equal to the slope of the line m and the line passes through the origin

therefore

in this problem

$f(x)=2x$ -----> represent a direct variation

Answer 2

When two variable quantities have a constant (unchanged) ratio, their relationship is called a direct variation. It is said that one variable "varies directly" as the other...simply when the y-intercept is zero.

So the best answer is f(x)=2x